Malicious content analysis with multi-version application support within single operating environment

ABSTRACT

Techniques for efficient and effective malicious content detection in plural versions of a software application are described herein. According to one embodiment, multiple versions of a software application are concurrently within a virtual machine (VM) executed within a data processing system. For each of the versions of the software application, a corresponding one of the versions is invoked to access a malicious content suspect within the VM without switching to another VM. The behaviors of each of the versions of the software application in response to the malicious content suspect is monitored to detect anomalous behavior indicative of malicious content in the malicious content suspect during execution of any of the versions of the software application. The detected anomalous behaviors, and, associated therewith, a version number corresponding to each of the versions of the software application whose execution resulted in the anomalous behavior are stored. An alert with respect to any indicated malicious content is issued.

FIELD OF THE INVENTION

Embodiments of the present invention relate generally to malicious content detection. More particularly, embodiments of the invention relate to performing a malicious content analysis using multiple versions of a software application associated with the malicious content suspect within a single operating environment.

BACKGROUND

Malicious software, or malware for short, may include any program or file that is harmful by design to a computer. Malware includes computer viruses, worms, Trojan horses, adware, spyware, and any programming that gathers information about a computer or its user or otherwise operates without permission. The owners of the computers are often unaware that these programs have been added to their computers and are often similarly unaware of their function.

Malicious network content is a type of malware distributed over a network via websites, e.g., servers operating on a network according to an HTTP standard or other well-known standard. Malicious network content distributed in this manner may be actively downloaded and installed on a computer, without the approval or knowledge of its user, simply by the computer accessing the web site hosting the malicious network content (the “malicious web site”). Malicious network content may be embedded within objects associated with web pages hosted by the malicious web site. Malicious network content may also enter a computer on receipt or opening of email. For example, email may contain an attachment, such as a portable document format (PDF) document, with embedded malicious executable programs. Furthermore, malicious content may exist in files contained in a computer memory or storage device, having infected those files through any of a variety of attack vectors.

Various processes and devices have been employed to prevent the problems associated with malicious content. For example, computers often run antivirus scanning software that scans a particular computer for viruses and other forms of malware. The scanning typically involves automatic detection of a match between content stored on the computer (or attached media) and a library or database of signatures of known malware. The scanning may be initiated manually or based on a schedule specified by a user or system administrator associated with the particular computer. Unfortunately, by the time malware is detected by the scanning software, some damage on the computer or loss of privacy may have already occurred, and the malware may have propagated from the infected computer to other computers. Additionally, it may take days or weeks for new signatures to be manually created, the scanning signature library updated and received for use by the scanning software, and the new signatures employed in new scans.

Moreover, anti-virus scanning utilities may have limited effectiveness to protect against all exploits by polymorphic malware. Polymorphic malware has the capability to mutate to defeat the signature match process while keeping its original malicious capabilities intact. Signatures generated to identify one form of a polymorphic virus may not match against a mutated form. Thus polymorphic malware is often referred to as a family of virus rather than a single virus, and improved anti-virus techniques to identify such malware families is desirable.

Another type of malware detection solution employs virtual environments to replay content within a sandbox established by virtual machines (VMs). Such solutions monitor the behavior of content during execution to detect anomalies that may signal the presence of malware. One such system offered by FireEye, Inc., the assignee of the present patent application, employs a two-phase malware detection approach to detect malware contained in network traffic monitored in real-time. In a first or “static” phase, a heuristic is applied to network traffic to identify and filter packets that appear suspicious in that they exhibit characteristics associated with malware. In a second or “dynamic” phase, the suspicious packets (and typically only the suspicious packets) are replayed within one or more virtual machines. For example, if a user is trying to download a file over a network, the file is extracted from the network traffic and analyzed in the virtual machine. The results of the analysis aids in determining whether the file is malicious. The two-phase malware detection solution may detect numerous types of malware and, even malware missed by other commercially available approaches. Through verification, the two-phase malware detection solution may also achieve a significant reduction of false positives relative to such other commercially available approaches. Dealing with false positives in malware detection may needlessly slow or interfere with download of network content or receipt of email, for example. This two-phase approach has even proven successful against many types of polymorphic malware and other forms of advanced persistent threats.

Some of the malicious content, such as a PDF file, may require a software application, such as an Adobe® Acrobat™ reader, to process (e.g., open or load in memory) in order to exhibit anomalous behavior indicative of malware and, in the real world, cause damage to a data processing system. Typically, in order to test for malware, the aforementioned two-phase malware detection system uses a single instance of the software application within the virtual environment. The VM has to be launched, tested, and terminated for the purpose of testing the potentially malicious content with the software application. It may take a relatively long time to launch and terminate a VM. In addition, in a data processing system, there is a limited number of VMs that can be concurrently launched because of limited resources (e.g., processor cores, memory). When a VM is scheduled, the potentially malicious content may be put in a pending queue until the necessary resources become available (e.g., another VM terminated). As a result, heavy workloads in terms of the number of potentially malicious content to be tested and VM instances needed for testing can tax system resources and cause undesirable test latencies.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.

FIG. 1 is a block diagram illustrating a malicious content detection system according to one embodiment of the invention.

FIG. 2 is a flow diagram illustrating a method for malicious content detection according to one embodiment of the invention.

FIG. 3 is a block diagram of a computer network system deploying a malicious content detection system according to one embodiment of the invention.

FIG. 4 is a block diagram illustrating an example of a data processing system which may be used with one embodiment of the invention.

DETAILED DESCRIPTION

Various embodiments and aspects of the inventions will be described with reference to details discussed below, and the accompanying drawings will illustrate the various embodiments. The following description and drawings are illustrative of the invention and are not to be construed as limiting the invention. Numerous specific details are described to provide a thorough understanding of various embodiments of the present invention. However, in certain instances, well-known or conventional details are not described in order to provide a concise discussion of embodiments of the present inventions.

Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in conjunction with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification do not necessarily all refer to the same embodiment.

Techniques for efficient and effective malicious content detection using plural versions of a software application are described herein. More specifically, embodiments of the invention obtain the advantages of testing across plural versions of a software application within a single operating environment required for cyber-attack analysis of a content suspect for identification of malware. With this approach, if any of the utilized versions of the software application have exploit vulnerabilities to the particular attack vector, it may be concluded that the content suspect contains malware.

A software application may be released in plural versions at least one of which may be susceptible to being infected by the malicious content while one or more of the others may not. As noted above, typically, the known two-phase malware detection systems only test with a single version of a software application. If the test is conducted with the version of the software application having the susceptibility, the test may then indicate that susceptibility for that version. If more than one version of the software application is executed, one after another, to test the same content suspect, testing resources and time may be unduly spent. On the other hand, if the testing is conducted on the content suspect using the single version of the software application, it may yield a false negative with respect to all other versions, since it is possible that only the version selected for use in the test is free of susceptibility to the particular attack. The testing across plural or even all versions of a software application may thus identify anomalous behavior linked to malware that would be missed using a more limited test protocol.

According to some embodiments, plural versions of a software application are preferably concurrently installed and maintained within a single VM. As used herein, “concurrent” indicates temporal overlap during testing. For example, if a particular software application is available in a number (greater than one), e.g., 10, different versions, all versions may be tested at the same time in the same VM, or, of course, a subset (e.g., five) may be tested in each of a limited number (e.g., two) of VMs, preferably less than the total number of versions to be tested. Continuing the former example, when the VM is launched, the 10 versions of the software application can be tested within the same VM without having to switch to and execute another VM. That is, processing logic does not have to terminate a current VM configured to test one version of the software application and launch another VM in order to test another version of the software application. In addition, since a single VM can be utilized to test multiple versions of a software application, the number of VMs required can be greatly reduced. As a result, the resources and time to schedule and maintain the VMs can also be reduced.

FIG. 1 is a block diagram illustrating a malicious content detection system according to one embodiment of the invention. Referring to FIG. 1, system 100 includes controller 101 to manage or control one or more virtual machines (VMs) 102 (also referred to as a sandboxed operating environment or simply a sandbox), where content associated with VMs 102 are stored in storage device 109 in a form of VM disk files 110.

Controller 101 may be implemented as part of a VM monitor or manager (VMM), also referred to as a hypervisor for managing or monitoring VMs, which may be hosted by a host operating system (OS). VM 102 may be hosted by a guest OS. The host OS and the guest OS may be the same type of operating systems or different types of operating systems (e.g., Windows™, Linux™, Unix™, Mac OS™, iOS™, etc.), or different versions thereof. A VM is a simulation of a machine (abstract or real) that is usually different from the target machine (where it is being simulated on). Virtual machines may be based on specifications of a hypothetical computer or emulate the computer architecture and functions of a real world computer. A virtual machine referred to herein can be any type of virtual machines, such as, for example, hardware emulation, full virtualization, para-virtualization, and operating system-level virtualization virtual machines.

According to one embodiment, when malicious content suspect 106 is received for a dynamic content analysis (as opposed to be a static content analysis described below), a scheduler 140 of controller 101 is configured to identify and select a VM, in this example VM 102, from a VM pool 145 that has been configured to closely simulate a target operating environment (e.g., particular version of an OS with particular version(s) of certain software installed therein) in which malicious content suspect 106 is to be analyzed. The scheduler 140 may include a queue of malicious content suspects waiting for a virtual machine to become available because, under heavy workloads, the number of VMs that may be concurrently executed may be limited. The scheduler 140 then launches VM 102 in which monitoring module 105 is running within VM 102 and configured to monitor activities and behavior of malicious content suspect 106.

In addition, monitoring module 105 maintains a persistent communication channel with analysis module 103 of controller 101 to communicate certain events or activities of malicious content suspect 106 during the execution. In response to detecting certain predetermined events triggered by malicious content suspect 106, monitoring module 105 is configured to send a message via the communication channel to analysis module 103, where the message may be recorded as part of event log 108. The message includes information identifying an event triggered by malicious content suspect 106. Event log 108 records events that have been selectively monitored and detected by monitoring module 103, such as, for example, file creation or file open events. Content of the event log 108 may be stored in a persistent storage as part of event log file(s) 112 of VM disk file 110 associated with VM 102. The recorded events may be analyzed by analysis module 103 based on a set of rules or policies (not shown) to determine whether malicious content suspect 106 is likely malicious.

According to one embodiment, prior to launching VM 102, one or more versions 131-133 of a software (SW) application that is associated with malicious content suspect 106 are installed and configured within VM 102. A SW application may be an Adobe Acrobat™ Reader and malicious content suspect 106 may be a PDF file. Alternatively, a SW application may be a Microsoft Office™ Suite and malicious content suspect 106 may be a WORD document file. Malicious content suspect 106 may include embedded codes or scripts that only exhibit anomalous behavior when the corresponding SW application accesses and loads malicious content suspect 106, including, for example, extracting or downloading suspect files 120 to be stored in the system. Indeed, the malicious content suspect 106 may exhibit the anomalous behavior for only a subset of the versions available for a SW application. This may be due to a security vulnerability (e.g., a programmatic feature susceptible to exploit) existing only in the subset of versions, which may occur, for example, when other versions have eliminated that feature or have been patched previously to close that security vulnerability. Accordingly, successfully detecting anomalous behavior marking a malicious attack may depend on the selection of the version or versions of the SW application to be used in testing conducted by the malicious content detection system 100. To that end, the controller 101 may further comprise a software selector and installer (“SSI”) 115. The SSI 115 selects one or more versions of a software application to be used in testing. For example, the SSI 115 may select a single software application version or plural versions in response to user input, where a user may be any individual such as a system administrator or a forensic specialist or other entity to equip to provide such input.

In one embodiment, the SSI 115 may determine a software profile best suitable for testing the malicious content suspect 106. The software profile may comprise the operating system (e.g., Windows™, Linux™), in a particular version, and a suitable software application, in a particular version, to simulate or mimic a particular digital device that runs those versions, in order to test whether that device is safe when processing the malicious content suspect 106. The determination can be based on analysis of the protocol information associated with the malicious content suspect 106. For purposes hereof, “version” shall include versioning of the software at any level, from new release through service packs (SPs). In an example, the SSI 115 determines that the software profile of network data is Windows® operating system, version Windows 7™, SP1 running Adobe Acrobat™ Reader X, version 10.1.4.

In other embodiments the SSI 115 may select a flight of different software application versions to enable the malicious content detection system 100 to detect anomalous behavior marking a malicious attack, for example, utilizing any security vulnerability present in any of the selected versions. For example, the selection may be based on an identification of all software application versions used within a particular organization, all commercially available, all available to the malicious content detection system 100, or some subset of any of the above or based on other factors. The decision as to the selection of software application versions may depend on the forensic objectives of the testing. Where the selected versions of the software application are not all compatible with the same operating system or operating system version, the SSI 115 may form groups of one or more the software application versions associated with each of required operating system or operating system version.

The SSI 115 may make the selection of version or versions of the software application in response to a user input entered via an input device 906 (FIG. 4). For example, the input device may allow a user to enter an operating system version and one or more software application versions using a command line interface. In some embodiments, a graphical user interface (GUI) may present a menu of one or more operating system versions along with one or more software application versions compatible with each of the operating system versions so as to allow a user to make an informed decision and selection. The SSI 155 will store the user selection and designate the selection for execution.

In one embodiment, the SSI 115 is responsible for configuring the VM 102 by installing the selected operating system version and software application version or versions in the VM 102. In another embodiment, the SSI 115 can retrieve a pre-configured VM 102 having the selected operating system version and software application version or versions already installed therein. In still another embodiment, the SSI 115 can designate the selected operating system version and software application version or versions for use by the scheduler 140, which is responsible for retrieving and/or configuring the VM 102.

Where the SSI 115 has formed groups of one or more the software application versions associated with each of a plurality of required operating system or operating system version, the SSI 115, or in other embodiments, the scheduler 140, may configure plural VMs 102 selected from a VM pool, each to process a different group of the software application versions on top of the required operating system or operating system version.

In one embodiment, multiple versions of a SW application may be installed by SSI 115 within VM 102 in different directories and/or under different identifiers (e.g., names), such that multiple versions of a single SW application can coexist with a single guest operating system. For example, for a Windows™ operating system, a SW application may be installed in different directories as follows:

-   -   C:\Program Files\SW Application\Version 1\ . . .     -   C:\Program Files\SW Application\ Version 2\ . . .     -   . . .     -   C:\Program Files\SW Application\ Version N\ . . .         In addition, in the Windows' registry, different versions of the         SW application may be registered under different identifiers or         names. As a result, the operating system may treat different         versions of the same SW application as different programs         installed therein. The multiple versions of a software         application may be installed by SSI 115 within VM 102 in the         different directories and/or under different names as entered by         a user, for example, using a command line interface.         Alternatively, the SSI 115 may automatically establish the         different directories and/or different names in response to user         input of the identity of the operating system version and         software application version, e.g., using the GUI as described         above. Alternatively, multiple versions of a SW application may         be installed within the same directory, but registered under         different identifiers or names within the operating system. For         example, the executables of multiple versions of a SW         application and/or their associated libraries can coexist within         the same directory with different filenames. The corresponding         operating system registry entries would have different links         that reference to different filenames.

According to one embodiment, monitoring module 105 launches each of the versions 131-133 to access malicious content suspect 106 within VM 102. For example, monitoring module 105 may launch each of the versions by passing as parameter an identifier (e.g., path/filename) identifying malicious content suspect 106. Monitoring module 105 monitors behavior of the corresponding version of the SW application to determine whether malicious content suspect 106 likely infects that particular version of the SW application. Monitoring module 105 may sequentially launch versions 131-133 of the SW application to access malicious content suspect 106. Alternatively, monitoring module 105 may launch multiple ones of the versions 131-133 and monitor their behaviors concurrently. Single monitoring module 105 may be configured to monitor multiple versions' behavior concurrently. Alternatively, multiple instances of monitoring module 105 may be utilized to concurrently monitor versions 131-133, respectively. Thus, a single VM can be utilized to test multiple versions of a SW application without having to switch to another VM. As a result, the time to schedule and/or launch a VM can be greatly reduced. A number of VMs and resources or bandwidth required to test a malicious content suspect can also be reduced.

According to another embodiment, the techniques described herein can also be utilized to determine whether a malicious content suspect could infect different applications. For example, a PDF file can be loaded by different browser applications (e.g., Internet Explorer™, or Firefox™) that are running within a single guest operating system of a virtual machine. In this example, multiple browser applications may be installed within the same guest operating system. Each of the browser applications can be utilized to open the PDF file and the behavior of the browser application is monitored to determine whether the PDF file likely infects the browser application, without having a need to switch to another virtual machine.

FIG. 2 is a flow diagram illustrating a method for malicious content detection according to one embodiment of the invention. Method 200 may be performed by system 100 of FIG. 1, which may be implemented as processing logic in software, hardware, or a combination thereof. Referring to FIG. 2, at block 201, processing logic installs and configures multiple versions of a SW application (e.g., Microsoft Office or Adobe Acrobat) within a single VM that is hosted by a guest OS. At block 202, in response to receiving a malicious content suspect associated with the SW application, processing logic identifies and launches a VM having multiple versions of the SW application installed therein. At block 203, for each of the versions of the SW application, processing logic invokes the corresponding version to access and test, preferably concurrently, the malicious content suspect therein. At block 204, processing logic monitors the behavior of the malicious content suspect processed with the corresponding version or versions of the SW application to identify anomalous behavior indicative of a malicious attack. At block 206, the processing logic stores information describing any detected anomalous behaviors, and, associated therewith, the version identifier (e.g., version number and, where applicable, service pack number) corresponding to each of the versions of the software application and the operating system whose execution resulted in the anomalous behavior. At block 208, processing logic declares any identified attack incident and may issue an alert, which in some embodiments, contains or references threat data, including, for example, the version number or numbers of the SW application having a potential security vulnerability so that remedial action may be taken.

For example, if a particular version number of a SW application is found to likely contain a security vulnerability as a result of testing in accordance with embodiments of the invention, it may be recommended that an IT department make a change to a different, existing version of that SW application throughout the organization it serves to prevent future exploits. Since these embodiments of the invention contemplate testing of multiple versions of the SW application, the change of versions may be effected with confidence if the new version selected is one that was tested and found not to have the same security vulnerability. Moreover, the alert may be issued beyond the organization so that other entities may be warned of the security vulnerability. Also, the software vendor may take steps to close the security vulnerability in all affected versions, through patching or issuing of a new, hardened version, with recommendations to its customers to upgrade.

FIG. 3 is a block diagram of an illustrative computer network system 800 having a malicious content detection system 850 in accordance with a further illustrative embodiment. The malicious content detection system 850 may represent any of the malicious content detection systems described above, such as, for example, detection system 100 of FIG. 1. The malicious content detection system 850 is illustrated with a server device 810 and a client device 830, each coupled for communication via a communication network 820. In various embodiments, there may be multiple server devices and multiple client devices sending and receiving data to/from each other, and the same device can serve as either a server or a client in separate communication sessions. Although FIG. 3 depicts data transmitted from the server device 810 to the client device 830, either device can transmit and receive data from the other.

Note that throughout this application, network content is utilized as an example of content for malicious content detection purposes; however, other types of content can also be applied. Network content may include any data transmitted over a network (i.e., network data). Network data may include text, software, images, audio, or other digital data. An example of network content includes web content, or any network data that may be transmitted using a Hypertext Transfer Protocol (HTTP), Hypertext Markup Language (HTML) protocol, or be transmitted in a manner suitable for display on a Web browser software application. Another example of network content includes email messages, which may be transmitted using an email protocol such as Simple Mail Transfer Protocol (SMTP), Post Office Protocol version 3 (POP3), or Internet Message Access Protocol (IMAP4). A further example of network content includes Instant Messages, which may be transmitted using an Instant Messaging protocol such as Session Initiation Protocol (SIP) or Extensible Messaging and Presence Protocol (XMPP). In addition, network content may include any network data that is transferred using other data transfer protocols, such as File Transfer Protocol (FTP).

The malicious network content detection system 850 may monitor exchanges of network content (e.g., Web content) in real-time rather than intercepting and holding the network content until such time as it can determine whether the network content includes malicious network content. The malicious network content detection system 825 may be configured to inspect exchanges of network content over the communication network 820, identify suspicious network content, and analyze the suspicious network content using a virtual machine to detect malicious network content. In this way, the malicious network content detection system 850 may be computationally efficient and scalable as data traffic volume and the number of computing devices communicating over the communication network 820 increase. Therefore, the malicious network content detection system 825 may not become a bottleneck in the computer network system 800.

The communication network 820 may include a public computer network such as the Internet, in which case a firewall 825 may be interposed between the communication network 820 and the client device 830. Alternatively, the communication network may be a private computer network such as a wireless telecommunication network, wide area network, or local area network, or a combination of networks. Though the communication network 820 may include any type of network and be used to communicate different types of data, communications of web data may be discussed below for purposes of example.

The malicious network content detection system 825 is shown as coupled with the network 820 by a network tap 840 (e.g., a data/packet capturing device). The network tap 840 may include a digital network tap configured to monitor network data and provide a copy of the network data to the malicious network content detection system 825. Network data may comprise signals and data that are transmitted over the communication network 820 including data flows from the server device 810 to the client device 830. In one example, the network tap 840 monitors and copies the network data without an appreciable decline in performance of the server device 810, the client device 830, or the communication network 820. The network tap 840 may copy any portion of the network data, for example, any number of data packets from the network data. In embodiments where the malicious content detection system 850 is implemented as a dedicated appliance or a dedicated computer system, the network tap 840 may include an assembly integrated into the appliance or computer system that includes network ports, network interface card and related logic (not shown) for connecting to the communication network 860 to non-disruptively “tap” traffic thereon and provide a copy of the traffic to the heuristic module 850. In other embodiments, the network tap 840 can be integrated into a firewall, router, switch or other network device (not shown) or can be a standalone component, such as an appropriate commercially available network tap. In virtual environments, a virtual tap (vTAP) can be used to copy traffic from virtual networks.

The network tap 840 may also capture metadata from the network data. The metadata may be associated with the server device 810 and/or the client device 830. For example, the metadata may identify the server device 810 and/or the client device 830. In some embodiments, the server device 810 transmits metadata which is captured by the tap 815. In other embodiments, a heuristic module 860 (described herein) may determine the server device 810 and the client device 830 by analyzing data packets within the network data in order to generate the metadata. The term, “content,” as used herein may be construed to include the intercepted network data and/or the metadata unless the context requires otherwise.

The malicious network content detection system 825 may include a heuristic module 860, a heuristics database 862, a scheduler 870, a virtual machine pool 880, an analysis engine 882 and a reporting module 884. In some embodiments, the network tap 840 may be contained within the malicious network content detection system 850.

The heuristic module 860 receives the copy of the network data from the network tap 840 and applies heuristics to the data to determine if the network data might contain suspicious network content. The heuristics applied by the heuristic module 860 may be based on data and/or rules stored in the heuristics database 862. The heuristic module 860 may examine the image of the captured content without executing or opening the captured content. For example, the heuristic module 860 may examine the metadata or attributes of the captured content and/or the code image (e.g., a binary image of an executable) to determine whether a certain portion of the captured content matches a predetermined pattern or signature that is associated with a particular type of malicious content. In one example, the heuristic module 860 flags network data as suspicious after applying a heuristic analysis. This detection process is also referred to as a static malicious content detection. The suspicious network data may then be provided to the scheduler 870. In some embodiments, the suspicious network data is provided directly to the scheduler 870 with or without buffering or organizing one or more data flows.

When a characteristic of the packet, such as a sequence of characters or keyword, is identified that meets the conditions of a heuristic, a suspicious characteristic of the network content is identified. The identified characteristic may be stored for reference and analysis. In some embodiments, the entire packet may be inspected (e.g., using deep packet inspection techniques) and multiple characteristics may be identified before proceeding to the next step. In some embodiments, the characteristic may be determined as a result of an analysis across multiple packets comprising the network content. A score related to a probability that the suspicious characteristic identified indicates malicious network content is determined.

The heuristic module 860 may also provide a priority level for the packet and/or the features present in the packet. The scheduler 870 may then load and configure a virtual machine from the virtual machine pool 880 in an order related to the priority level, and dispatch the virtual machine to the analysis engine 882 to process the suspicious network content.

The heuristic module 860 may provide the packet containing the suspicious network content to the scheduler 870, along with a list of the features present in the packet and the malicious probability scores associated with each of those features. Alternatively, the heuristic module 860 may provide a pointer to the packet containing the suspicious network content to the scheduler 870 such that the scheduler 870 may access the packet via a memory shared with the heuristic module 860. In another embodiment, the heuristic module 860 may provide identification information regarding the packet to the scheduler 870 such that the scheduler 870, replayer 805, or virtual machine may query the heuristic module 860 for data regarding the packet as needed.

The scheduler 870 may identify the client device 830 and retrieve a virtual machine associated with the client device 830. A virtual machine may itself be executable software that is configured to mimic the performance of a device (e.g., the client device 830). The virtual machine may be retrieved from the virtual machine pool 880. Furthermore, the scheduler 870 may identify, for example, a Web browser running on the client device 830, and retrieve a virtual machine associated with the web browser.

In some embodiments, the heuristic module 860 transmits the metadata identifying the client device 830 to the scheduler 870. In other embodiments, the scheduler 870 receives one or more data packets of the network data from the heuristic module 860 and analyzes the one or more data packets to identify the client device 830. In yet other embodiments, the metadata may be received from the network tap 840.

The scheduler 870 may retrieve and configure the virtual machine to mimic the pertinent performance characteristics of the client device 830. In one example, the scheduler 870 configures the characteristics of the virtual machine to mimic only those features of the client device 830 that are affected by the network data copied by the network tap 840. The scheduler 870 may determine the features of the client device 830 that are affected by the network data by receiving and analyzing the network data from the network tap 840. Such features of the client device 830 may include ports that are to receive the network data, select device drivers that are to respond to the network data, and any other devices coupled to or contained within the client device 830 that can respond to the network data. In other embodiments, the heuristic module 860 may determine the features of the client device 830 that are affected by the network data by receiving and analyzing the network data from the network tap 840. The heuristic module 850 may then transmit the features of the client device to the scheduler 870.

The virtual machine pool 880 may be configured to store one or more virtual machines. The virtual machine pool 880 may include software and/or a storage medium capable of storing software. In one example, the virtual machine pool 880 stores a single virtual machine that can be configured by the scheduler 870 to mimic the performance of any client device 830 on the communication network 820. The virtual machine pool 880 may store any number of distinct virtual machines that can be configured to simulate the performance of a wide variety of client devices 830. The virtual machine(s) may be executed along with a plurality of versions of a software application for dynamic testing of network content, as described hereinabove.

The analysis engine 882 simulates the receipt and/or display of the network content from the server device 810 after the network content is received by the client device 110 to analyze the effects of the network content upon the client device 830. The analysis engine 882 may identify the effects of malware or malicious network content by analyzing the simulation of the effects of the network content upon the client device 830 that is carried out on the virtual machine. There may be multiple analysis engines 850 to simulate multiple streams of network content. The analysis engine 882 may be configured to monitor the virtual machine for indications that the suspicious network content is in fact malicious network content. Such indications may include unusual network transmissions, unusual changes in performance, and the like. This detection process is referred to as a dynamic malicious content detection.

The analysis engine 882 may flag the suspicious network content as malicious network content according to the observed behavior of the virtual machine. The reporting module 884 may issue alerts indicating the presence of malware, and using pointers and other reference information, identify the packets of the network content containing the malware. Additionally, the server device 810 may be added to a list of malicious network content providers, and future network transmissions originating from the server device 810 may be blocked from reaching their intended destinations, e.g., by firewall 825.

The computer network system 800 may also include a further communication network 890, which couples the malicious content detection system (MCDS) 850 with one or more other MCDS, of which MCDS 892 and MCDS 894 are shown, and a management system 896, which may be implemented as a Web server having a Web interface. The communication network 890 may, in some embodiments, be coupled for communication with or part of network 820. The management system 896 is responsible for managing the MCDS 850, 892, 894 and providing updates to their operation systems and software programs. Also, the management system 896 may cause malware signatures generated by any of the MCDS 850, 892, 894 to be shared with one or more of the other MCDS 850, 892, 894, for example, on a subscription basis. Moreover, the malicious content detection system as described in the foregoing embodiments may be incorporated into one or more of the MCDS 850, 892, 894, or into all of them, depending on the deployment. Also, the management system 896 itself or another dedicated computer station may incorporate the malicious content detection system in deployments where such detection is to be conducted at a centralized resource.

Further information regarding an embodiment of a malicious content detection system can be had with reference to U.S. Pat. No. 8,171,553, the disclosure of which being incorporated herein by reference in its entirety.

As described above, the detection or analysis performed by the heuristic module 860 may be referred to as static detection or static analysis, which may generate a first score (e.g., a static detection score) according to a first scoring scheme or algorithm. The detection or analysis performed by the analysis engine 882 is referred to as dynamic detection or dynamic analysis, which may generate a second score (e.g., a dynamic detection score) according to a second scoring scheme or algorithm. The first and second scores may be combined, according to a predetermined algorithm, to derive a final score indicating the probability that a malicious content suspect is indeed malicious.

Furthermore, detection systems 850 and 892-894 may deployed in a variety of distribution ways. For example, detection system 850 may be deployed as a detection appliance at a client site to detect any suspicious content, for example, at a local area network (LAN) of the client. In addition, any of MCDS 892 and MCDS 894 may also be deployed as dedicated data analysis systems. Systems 850 and 892-894 may be configured and managed by a management system 896 over network 890, which may be a LAN, a wide area network (WAN) such as the Internet, or a combination of both. Management system 896 may be implemented as a Web server having a Web interface to allow an administrator of a client (e.g., corporation entity) to log in to manage detection systems 850 and 892-894. For example, an administrator may able to activate or deactivate certain functionalities of malicious content detection systems 850 and 892-894 or alternatively, to distribute software updates such as malicious content definition files (e.g., malicious signatures or patterns) or rules, etc. Furthermore, a user can submit via a Web interface suspicious content to be analyzed, for example, by dedicated data analysis systems 892-894. As described above, malicious content detection includes static detection and dynamic detection. Such static and dynamic detections can be distributed amongst different systems over a network. For example, static detection may be performed by detection system 850 at a client site, while dynamic detection of the same content can be offloaded to the cloud, for example, by any of detection systems 892-894. Other configurations may exist.

FIG. 4 is a block diagram illustrating an example of a data processing system which may be used with one embodiment of the invention. For example, system 900 may represents any of data processing systems described above performing any of the processes or methods described above. System 900 may represent a desktop, a tablet, a server, a mobile phone, a media player, a personal digital assistant (PDA), a personal communicator, a gaming device, a network router or hub, a wireless access point (AP) or repeater, a set-top box, or a combination thereof.

Referring to FIG. 4, in one embodiment, system 900 includes processor 901 and peripheral interface 902, also referred to herein as a chipset, to couple various components to processor 901 including memory 903 and devices 905-908 via a bus or an interconnect. Processor 901 may represent a single processor or multiple processors with a single processor core or multiple processor cores included therein. Processor 901 may represent one or more general-purpose processors such as a microprocessor, a central processing unit (CPU), or the like. More particularly, processor 901 may be a complex instruction set computing (CISC) microprocessor, reduced instruction set computing (RISC) microprocessor, very long instruction word (VLIW) microprocessor, or processor implementing other instruction sets, or processors implementing a combination of instruction sets. Processor 901 may also be one or more special-purpose processors such as an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a digital signal processor (DSP), a network processor, a graphics processor, a network processor, a communications processor, a cryptographic processor, a co-processor, an embedded processor, or any other type of logic capable of processing instructions. Processor 901 is configured to execute instructions for performing the operations and steps discussed herein.

Peripheral interface 902 may include memory control hub (MCH) and input output control hub (ICH). Peripheral interface 902 may include a memory controller (not shown) that communicates with a memory 903. Peripheral interface 902 may also include a graphics interface that communicates with graphics subsystem 904, which may include a display controller and/or a display device. Peripheral interface 902 may communicate with graphics device 904 via an accelerated graphics port (AGP), a peripheral component interconnect (PCI) express bus, or other types of interconnects.

An MCH is sometimes referred to as a Northbridge and an ICH is sometimes referred to as a Southbridge. As used herein, the terms MCH, ICH, Northbridge and Southbridge are intended to be interpreted broadly to cover various chips who functions include passing interrupt signals toward a processor. In some embodiments, the MCH may be integrated with processor 901. In such a configuration, peripheral interface 902 operates as an interface chip performing some functions of the MCH and ICH. Furthermore, a graphics accelerator may be integrated within the MCH or processor 901.

Memory 903 may include one or more volatile storage (or memory) devices such as random access memory (RAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), static RAM (SRAM), or other types of storage devices. Memory 903 may store information including sequences of instructions that are executed by processor 901, or any other device. For example, executable code and/or data of a variety of operating systems, device drivers, firmware (e.g., input output basic system or BIOS), and/or applications can be loaded in memory 903 and executed by processor 901. An operating system can be any kind of operating systems, such as, for example, Windows® operating system from Microsoft®, Mac OS®/iOS® from Apple, Android® from Google®, Linux®, Unix®, or other real-time or embedded operating systems such as VxWorks.

Peripheral interface 902 may provide an interface to IO devices such as devices 905-908, including wireless transceiver(s) 905, input device(s) 906, audio IO device(s) 907, and other IO devices 908. Wireless transceiver 905 may be a WiFi transceiver, an infrared transceiver, a Bluetooth transceiver, a WiMax transceiver, a wireless cellular telephony transceiver, a satellite transceiver (e.g., a global positioning system (GPS) transceiver) or a combination thereof. Input device(s) 906 may include a mouse, a touch pad, a touch sensitive screen (which may be integrated with display device 904), a pointer device such as a stylus, and/or a keyboard (e.g., physical keyboard or a virtual keyboard displayed as part of a touch sensitive screen). For example, input device 906 may include a touch screen controller coupled to a touch screen. The touch screen and touch screen controller can, for example, detect contact and movement or break thereof using any of a plurality of touch sensitivity technologies, including but not limited to capacitive, resistive, infrared, and surface acoustic wave technologies, as well as other proximity sensor arrays or other elements for determining one or more points of contact with the touch screen.

Audio IO 907 may include a speaker and/or a microphone to facilitate voice-enabled functions, such as voice recognition, voice replication, digital recording, and/or telephony functions. Other optional devices 908 may include a storage device (e.g., a hard drive, a flash memory device), universal serial bus (USB) port(s), parallel port(s), serial port(s), a printer, a network interface, a bus bridge (e.g., a PCI-PCI bridge), sensor(s) (e.g., a motion sensor, a light sensor, a proximity sensor, etc.), or a combination thereof. Optional devices 908 may further include an imaging processing subsystem (e.g., a camera), which may include an optical sensor, such as a charged coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) optical sensor, utilized to facilitate camera functions, such as recording photographs and video clips.

Note that while FIG. 4 illustrates various components of a data processing system, it is not intended to represent any particular architecture or manner of interconnecting the components; as such details are not germane to embodiments of the present invention. It will also be appreciated that network computers, handheld computers, mobile phones, and other data processing systems which have fewer components or perhaps more components may also be used with embodiments of the invention.

Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as those set forth in the claims below, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

The techniques shown in the figures can be implemented using code and data stored and executed on one or more electronic devices. Such electronic devices store and communicate (internally and/or with other electronic devices over a network) code and data using computer-readable media, such as non-transitory computer-readable storage media (e.g., magnetic disks; optical disks; random access memory; read only memory; flash memory devices; phase-change memory) and transitory computer-readable transmission media (e.g., electrical, optical, acoustical or other form of propagated signals—such as carrier waves, infrared signals, digital signals).

The processes or methods depicted in the preceding figures may be performed by processing logic that comprises hardware (e.g. circuitry, dedicated logic, etc.), firmware, software (e.g., embodied on a non-transitory computer readable medium), or a combination of both. Although the processes or methods are described above in terms of some sequential operations, it should be appreciated that some of the operations described may be performed in a different order. Moreover, some operations may be performed in parallel rather than sequentially.

In the foregoing specification, embodiments of the invention have been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications may be made thereto without departing from the broader spirit and scope of the invention as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense. 

What is claimed is:
 1. A computer-implemented method for detecting malicious content, the method comprising: installing a plurality of versions of a software application concurrently within a virtual machine by at least registering each of the plurality of versions of the software application with an operating system of the virtual machine under different identifiers, each of the plurality of versions of the software application being different from each other; selecting, by logic within a virtual machine monitor being executed by a processor of a data processing system, a subset of the plurality of versions of the software application that are concurrently installed within the virtual machine that is executed within the data processing system; processing one or more software application versions of the subset of the plurality of versions of the software application to access a malicious content suspect within the virtual machine, without switching to another virtual machine; monitoring, by a monitoring module, behaviors of the malicious content suspect during processing by one or more software application versions of the subset of the plurality of versions of the software application to detect behaviors associated with a malicious attack; storing information associated with the detected behaviors that are associated with a malicious attack; and issuing an alert with respect to any detected malicious content.
 2. The method of claim 1, wherein the installing of the plurality of versions of the software application comprises installing the plurality of versions of the software application in a plurality of virtual machines configured in a virtual machine pool, each virtual machine of the plurality of virtual machines being associated with a specific version of a guest operating system.
 3. The method of claim 1, wherein the installing of the plurality of versions of the software application further comprises installing a first software application version of the subset of the plurality of versions of the software application in a first directory and installing a second software application version of the subset of the plurality of versions of the software application in a second separate directory different than the first directory.
 4. The method of claim 1, wherein the registering of each of the plurality of versions of the software application with the operating system is conducted using a different, separate application identifier for each of the plurality of versions of the software application.
 5. The method of claim 1, wherein the installing of the plurality of versions of the software application further comprises installing each of the plurality of versions of the software application in an identical directory.
 6. The method of claim 1, wherein the processing of the one or more software application versions of the subset of the plurality of versions of the software application comprises processing each software application version of the subset of the plurality of versions of the software application by at least launching each software application version of the subset of the plurality of versions of the software application within the virtual machine in response to providing an identifier identifying the malicious content suspect to allow each of the launched software application versions of the subset of the plurality of versions of the software application to process the malicious content suspect.
 7. The method of claim 2, further comprising: based on information associated with the malicious content suspect, selecting by a scheduler the virtual machine from the virtual machine pool that has been configured to mimic a target operating environment of malicious content suspect; and scheduling, by the scheduler, the selected virtual machine to be launched within the data processing system.
 8. The method of claim 1, wherein the alert comprises an identifier of at least one software application version of the subset of the plurality of versions of the software application with the detected behaviors associated with a malicious attack.
 9. A non-transitory machine-readable medium storing instructions, which when executed by a processor, cause the processor to perform operations comprising: installing a plurality of versions of a software application concurrently within a virtual machine by at least registering each of the plurality of versions of the software application with an operating system of the virtual machine under different identifiers, each of the plurality of versions of the software application being different from each other; selecting, by logic within a virtual machine monitor operating on a processor of a data processing system, a subset of the plurality of versions of the software application that are concurrently installed within the virtual machine that is executed within the data processing system; for one or more software application versions of the subset of the plurality of versions of the software application, processing the corresponding software application version to access a malicious content suspect within the virtual machine without switching to another virtual machine; monitoring behaviors of the malicious content suspect during execution by the one or more software application versions of the subset of the plurality of versions of the software application to detect behaviors associated with a malicious attack during execution of any of the one or more software application versions; storing information associated with the detected behaviors that are associated with a malicious attack; and issuing an alert with respect to any indicated malicious content, the alert comprises an identifier of the software application version with the detected behaviors.
 10. The non-transitory machine-readable medium of claim 9, wherein the installing of the plurality of versions of the software application comprises installing the plurality of versions of the software application in a plurality of virtual machines configured in a virtual machine pool, each virtual machine of the plurality of virtual machines being associated with a specific version of a guest operating system.
 11. The non-transitory machine-readable medium of claim 9, wherein the installing of the plurality of versions of the software application further comprises installing a first software application version of the subset of the plurality of versions of the software application in a first directory and installing a second software application version of the plurality of versions of the software application in a second separate directory different than the first directory.
 12. The non-transitory machine-readable medium of claim 9, wherein the registering of each of the plurality of versions of the software application comprises registering each of the plurality of versions of the software application that are different from each other with a guest operating system using the different identifiers.
 13. The non-transitory machine-readable medium of claim 9, wherein the installing of the plurality of versions of the software application further comprises installing each software application version of the plurality of versions of the software application in an identical directory.
 14. The non-transitory machine-readable medium of claim 9, wherein the processing operations performed by the processor comprises sequentially launching the one or more of the software application versions of the subset of the plurality of versions of the software application within the virtual machine in response to providing an identifier identifying the malicious content suspect to allow each of the one or more launched software application versions to process the malicious content suspect.
 15. The non-transitory machine-readable medium of claim 9, wherein the operations further comprise: based on information associated with the malicious content suspect, selecting by a scheduler the virtual machine from a virtual machine pool that has been configured to mimic a target operating environment of malicious content suspect; and scheduling by the scheduler the virtual machine to be launched within the data processing system.
 16. The non-transitory machine-readable medium of claim 15, wherein the subset of the plurality of versions of the software application are tested in processing the malicious content suspect within the virtual machine, without having to schedule, launch, and terminate an individual virtual machine for each of the subset of the plurality of versions of the software application.
 17. A malicious content detection system, comprising: a processor; and a memory coupled to the processor, the memory to store instructions, including instructions that, when executed, cause the processor to install a plurality of versions of a software application concurrently within a virtual machine by at least registering each of the plurality of versions of the software application with an operating system of the virtual machine under different identifiers, each of the plurality of versions of the software application being different from each other, select, by logic within a virtual machine monitor, a subset of the plurality of versions of the software application that are concurrently installed within a virtual machine that is executed within the malicious content detection system, process one or more software application versions of the subset of the plurality of versions of the software application to access a malicious content suspect within the virtual machine, without switching to another virtual machine, monitor behaviors of the malicious content suspect during processing by each software application version of the subset of the plurality of versions of the software application in response to the malicious content suspect to detect a behavior associated with a malicious attack, store information associated with the detected behavior associated with a malicious attack, and issue an alert with respect to any detected malicious content.
 18. The malicious content detection system of claim 17, wherein the processor to install the plurality of versions of the software application in a plurality of virtual machines configured in a virtual machine pool, each virtual machine of the plurality of virtual machines being associated with a specific version of a guest operating system.
 19. The malicious content detection system of claim 17, wherein the installing of the plurality of versions of the software application further comprises installing a unique directory path corresponding to each software application version of the subset of the plurality of versions of the software application.
 20. The malicious content detection system of claim 17, wherein registering of each of the plurality of versions of the software application with the operating system is performed using a different identifier for each of the plurality of versions of the software application.
 21. The malicious content detection system of claim 17, wherein the processor is to sequentially launch the one or more software application versions of the subset of the plurality of versions of the software application within the virtual machine in response to providing an identifier identifying the malicious content suspect to allow the launched version of the software application to process the malicious content suspect.
 22. The malicious content detection system of claim 17, further comprising a scheduler executed in the memory by the processor to based on information associated with the malicious content suspect, select the virtual machine from a virtual machine pool that has been configured to mimic a target operating environment of malicious content suspect; and schedule the virtual machine to be launched within the malicious content detection system.
 23. The malicious content detection system of claim 22, wherein the subset of the plurality of versions of the software application are tested in processing the malicious content suspect within the virtual machine, without having to schedule, launch, and terminate an individual virtual machine for each software application version for the subset of the plurality of versions of the software application.
 24. The method of claim 6, wherein the launching of each software application version of the subset of the plurality of versions of the software application within the virtual machine comprises launching multiple versions of the software application concurrently.
 25. The method of claim 1, wherein the processing of the one or more software application versions of the subset of the plurality of versions of the software application comprises processing each software application version of the subset of the plurality of versions of the software application being lesser in number than the plurality of versions of the software application.
 26. The method of claim 25, wherein each software application version of the subset of the plurality of versions of the software application is a new release of the software application.
 27. The method of claim 25, wherein each software application version of the subset of the plurality of versions of the software application is either a new release of the software application or a modification of the software application through a service pack.
 28. The method of claim 25, wherein prior to installing of the plurality of versions of the software application, the method further comprising: generating a graphical user interface that displays a menu including one or more operating system versions along with versions of software applications compatible with each of the one or more operating system versions that includes the operating system for use in selecting the subset of the plurality of versions of the software application.
 29. The method of claim 1, wherein the subset of the plurality of versions of the software application is equal in number to the plurality of versions of the software application.
 30. The method of claim 1, wherein the installing of the plurality of versions of the software application concurrently within the virtual machine is conducted by the logic within the virtual machine monitor that receives information that identifies selected versions of the software application that correspond to the subset of the plurality of versions of the software application.
 31. The method of claim 1, wherein prior to installing of the plurality of versions of the software application, the method further comprising: generating a graphical user interface that displays a menu including at least the plurality of versions of the software application that are compatible with the operating system.
 32. The method of claim 1, wherein the selecting of the subset of the plurality of versions of the software application is based, at least in part, on input provided by an individual including a system administrator.
 33. The non-transitory machine-readable medium of claim 9, wherein the processor to process each software application version of the subset of the plurality of versions of the software application being lesser in number than the plurality of versions of the software application.
 34. The non-transitory machine-readable medium of claim 33, wherein the stored information associated with the detected behaviors includes the detected behaviors and a version number corresponding to a software application version of the subset of the plurality of versions of the software application whose execution resulted in the detected behaviors.
 35. The non-transitory machine-readable medium of claim 33, wherein each software application version of the subset of the plurality of versions of the software application is a new release of the software application.
 36. The non-transitory machine-readable medium of claim 33, wherein each software application version of the subset of the plurality of versions of the software application is either a new release of the software application or a modification of the software application through a service pack.
 37. The non-transitory machine-readable medium of claim 33, wherein prior to installing of the plurality of versions of the software application, the method further comprising: generating a graphical user interface that displays a menu including one or more operating system versions along with versions of software applications compatible with each of the one or more operating system versions that include the operating system for use in selecting the subset of the plurality of versions of the software application.
 38. The non-transitory machine-readable medium of claim 9, wherein the subset of the plurality of versions of the software application is equal in number to the plurality of versions of the software application.
 39. The non-transitory machine-readable medium of claim 9, wherein the installing of the plurality of versions of the software application concurrently within the virtual machine is conducted by logic within the virtual machine monitor that receives information that identifies selected versions of the software application that correspond to the subset of the plurality of versions of the software application.
 40. The non-transitory machine-readable medium of claim 9, wherein prior to installing of the plurality of versions of the software application, the operations performs by the processor further comprising: generating a graphical user interface that displays a menu including at least the plurality of versions of the software application that are compatible with the operating system for use in selecting of the subset of the plurality of versions of the software application.
 41. The non-transitory machine-readable medium of claim 9, wherein the selecting of the subset of the plurality of versions of the software application is based, at least in part, on input provided by an individual including a system administrator.
 42. The malicious content detection system of claim 17, wherein the processor to process the one or more software application versions of the subset of the plurality of versions of the software application by processing each software application version of the subset of the plurality of versions of the software application being lesser in number than the plurality of versions of the software application.
 43. The malicious content detection system of claim 42, wherein the information associated with the detected behavior includes the detected behavior and a version number corresponding to a software application version of the subset of the plurality of versions of the software application whose execution resulted in the detected behavior.
 44. The malicious content detection system of claim 42, wherein each software application version of the subset of the plurality of versions of the software application is a new release of the software application.
 45. The malicious content detection system of claim 42, wherein each software application version of the subset of the plurality of versions of the software application is either a new release of the software application or a modification of the software application through a service pack.
 46. The malicious content detection system of claim 17, wherein the subset of the plurality of versions of the software application is equal in number to the plurality of versions of the software application.
 47. The malicious content detection system of claim 17, wherein prior to the install of the plurality of versions of the software application, the processor further performs operations comprising: generating a graphical user interface that displays a menu including one or more operating system versions along with versions of software applications compatible with each of the one or more operating system versions that includes the operating system for use in selecting the subset of the plurality of versions of the software application.
 48. The malicious content detection system of claim 17, wherein prior to the install of the plurality of versions of the software application, the processor further generates a graphical user interface that displays a menu including at least the plurality of versions of the software application that are compatible with the operating system for use in selecting the subset of the plurality of versions of the software application.
 49. The malicious content detection system of claim 17, wherein the processor to select the subset of the plurality of versions of the software application based on input provided by an individual including a system administrator. 